Motor control apparatus

A motor control apparatus controlling current feeding to a motor and a rotational direction of the motor by operating a switch in an H-bridge circuit, comprising:

• four bridge-circuit switches that are arranged between a high potential line and a low potential line, and constitute the H-bridge circuit in which a first half-bridge circuit and a second half-bridge circuit are connected in parallel;
• two current feeding line switches that are arranged at a current feeding line connected through the motor between a first node as an intermediate point of the first half-bridge circuit and a second node as an intermediate point of the second half-bridge circuit, and are connected in series so as to arrange two parasitic diodes facing each other in the two current feeding line switches;
• a pull-up resistor that is connected between the high potential line and a third node, which is arranged between the two current feeding line switches on the current feeding line;
• a pull-down resistor that is connected between the low potential line and a fourth node, which is arranged at an opposite side of the third node such that the motor is interposed between the third node and the fourth node on the current feeding line;
• a protective diode that is connected to at least one of the pull-up resistor and the pull-down resistor, and blocks a current flowing from a low potential side to a high potential side;
• and
• a fault diagnostic device that includes:
• a driving circuit that turns on or off the four bridge-circuit switches and the two current feeding line switches;
• and
• a voltage determinator that determines suitability of a first voltage at the first node and a second voltage at the second node,
• wherein the fault diagnostic device carries out initial fault diagnosis for at least one of the four bridge circuit switches and the two current feeding line switches based on the first voltage and the second voltage before driving of the motor.